Put the O2 bung about 18-24 inches away from the housing outlet (where the downpipe begins from the turbo). Try to make sure you don't put the O2 sensor too close to the tip of the exhaust either, or it could give false readings as ambient air circulates around the edge. I'd also advise mounting the sensor either on top of the pipe, or on the side. Don't tap the bottom of the downpipe, because condensation can collect there which will damage the sensor over time.

It'd be easiest if you showed us a picture, but basically you don't want it super close to the turbo, nor do you want it super close to the tip.

 

And if you do happen to notice condensation and don't want it to get damaged, check out my latest thread on timer delay relay. It's a cheap "insurance" so you won't have to replace the O2 sensor sooner than you need to.

 

 

A turbocharged Honda isn't really difficult. Tips and information are readily available these days, compared to back in the earlier days of modifying Hondas. You just have to have persistence and willingness to learn.

 

the question has already been answered here. But I'll also state that the answer to your question is also included in the instructions that come with all widebands.
I'll add that you want it to be at least 6" before the opening of the pipe. Any less than that and it definitely will read terribly inaccurate.